Making a soft tissue prosthesis for repairing a defect of an abdominal wall or a pelvic cavity wall

ABSTRACT

Surgical prostheses and methods of using and making surgical prostheses are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of and claims priority toU.S. application Ser. No. 11/103,967, filed on Apr. 12, 2005, whichapplication claims priority to U.S. Application Ser. No. 60/563,836,filed on Apr. 20, 2004, the entire contents of both are incorporated byreference herein.

TECHNICAL FIELD

This invention relates to surgical prostheses, and more particularly toa surgical prosthesis used to repair an opening in a body cavity.

BACKGROUND

An unwanted opening in a body cavity, such as an incisional hernia, isoften repaired using a prosthetic mesh, such as a polypropylene mesh ora polypropylene mesh including a biodegradable, adhesion barrier layeras described in PCT publication number WO 01/43789 and U.S. Pat. No.6,264,702, to line the inner surface of the body cavity at the wallopening.

SUMMARY

In general, in one aspect, the invention features a surgical prosthesis.The surgical prosthesis includes a three-dimensional mesh including atleast two types of yarn interlooped or intertwined to define at leasttwo layers, wherein one of the at least two layers is substantiallynon-biodegradable and another of the at least two layers issubstantially biodegradable. An adhesion barrier is interconnected withthe second, substantially biodegradable layer of the three-dimensionalmesh.

Embodiments may include one or more of the following features. One ofthe at least two types of yarn within the three-dimensional mesh is anon-biodegradable yarn. The non-biodegradable yarn is selected frompolypropylene, polyethylene terephthalate or a combination thereof. Thenon-biodegradable yarn has a diameter of about 0.001 to about 0.010inches, and is preferably about 0.005 inches.

Embodiments may also include one or more of the following features. Oneof the at least two types of yarn is a biodegradable yarn. Thebiodegradable yarn is selected from poly(glycolic) acid, polylacticacid, polydioxanone, polycaprolactone, calcium alginate or a combinationthereof. The biodegradable yarn has a diameter of no greater than about120 denier. In certain embodiments, the biodegradable yarn has adiameter no greater than about 100 denier.

In some embodiments, the three-dimensional mesh of the surgicalprosthesis includes at least one non-biodegradable monofilament yarn andat least one biodegradable multifilament yarn. In some embodiments, thethree-dimensional mesh of the surgical prosthesis includes at least onenon-biodegradable monofilament yarn and at least two biodegradablemultifilament yarns.

Embodiments may also include one or more of the following features. Theadhesion barrier of the surgical prosthesis includes polymer hydrogel.The adhesion barrier includes at least one polyanionic polysaccharidemodified by reaction with carbodiimide. In some embodiments, theadhesion barrier includes a crosslinked polymer hydrogel alone or incombination with at least one polyanionic polysaccharide modified byreaction with carbodiimide. The crosslinked polymer hydrogel includesone or more hydrophilic blocks, one or more biodegradable blocks, andone or more crosslinking blocks. The crosslinked polymer hydrogel isformed by polymerization of monomers including photopolymerizablepoly(ethylene glycol)-trimethlyene carbonate/lactate multi-blockpolymers endcapped with acrylate esters. The polyanionic polysaccharidemodified by reaction with carbodiimide includes carbodiimide-modifiedhyaluronic acid and carbodiimide-modified carboxymethylcellulose.

Embodiments may also include one or more of the following features. Theadhesion barrier is in the form of a film, a foam, or a gel. Theadhesion barrier has a density of about 5 grams total polymer per squarefoot. The surgical prosthesis has a moisture content of less than about2%. In some embodiments, the surgical prosthesis has a moisture contentless than about 1.2%.

In another aspect, the invention features a surgical prosthesisincluding a first layer formed substantially of a non-biodegradableyarn, a second layer formed substantially of a first biodegradable yarn,and an adhesion barrier embedded within the second layer. The first andsecond layers of the surgical prosthesis are connected with a secondbiodegradable yarn. The first layer defines a first outer surface of thesurgical prosthesis and the adhesion barrier defines a second outersurface of the surgical prosthesis, wherein the first outer surface hasa macroporous structure adapted to permit tissue ingrowth into the firstlayer and the second outer surface of the surgical prosthesis is adaptedto minimize the formation of adhesion of tissue adjacent to the secondouter surface.

Embodiments may include one or more of the following features. Thesecond outer surface of the surgical prosthesis has a microporousstructure having a pore size of about 10 microns or less. Themacroporous structure of the first outer surface of the surgicalprosthesis has a pore size of about 100 microns or more.

Embodiments may also include one or more of the following features. Thenon-biodegradable yarn is selected from polypropylene, polyethyleneterephthalate or a combination thereof. The first biodegradable yarn isselected from poly(glycolic) acid, polylactic acid, polydioxanone,polycaprolactone, calcium alginate or combinations thereof. The secondbiodegradable yarn is selected from poly(glycolic) acid, polylacticacid, polydioxanone, polycaprolactone, calcium alginate or combinationsthereof.

Embodiments may also include one or more of the following. The adhesionbarrier includes a crosslinked polymer hydrogel and at least onepolyanionic polysaccharide modified by reaction with carbodiimide. Thecrosslinked polymer hydrogel includes one or more hydrophilic blocks,one or more biodegradable blocks, and one or more crosslinking blocks.In some embodiments, the crosslinked polymer hydrogel is formed bypolymerization of monomers including photopolymerizable poly(ethyleneglycol)-trimethlyene carbonate/lactate multi-block polymers endcappedwith acrylate esters. The polyanionic polysaccharide modified byreaction with carbodiimide includes carbodiimide-modified hyaluronicacid and carbodiimide-modified carboxymethylcellulose.

In general, in a further aspect, the invention features a method ofmaking a surgical prosthesis. The method includes the steps of providinga fabric including a first layer formed substantially ofnon-biodegradable yarn and a second layer formed of biodegradable yarn,providing a liquid formulation including macromers and an initiator,placing the fabric with the liquid formulation such that the secondlayer is in fluid contact with the liquid formulation; and exposing theliquid formulation to a light source.

Embodiments may include one or more of the following. The light sourceused is an LED array having an intensity of about 1 to about 100 mW/cm².The initiator used within the liquid formulation is a photoinitiator,such as for example, Eosin Y. The liquid formulation further includesbiopolymers, an accelerant, and a buffer. The biopolymers include atleast one polyanionic polysaccharide modified by reaction withcarbodiimide. The buffer includes triethanolamine and/or potassiumphosphate. The accelerant includes N-vinylcaprolactam. In someembodiments, the liquid formulation includes 1 weight percentcarbodiimide-modified hyaluronic acid and carbodiimide-modifiedcarboxymethylcellulose, 2.5 weight percent poly(ethyleneglycol)-trimethlyene carbonate/lactate multi-block polymers endcappedwith acrylate esters, 40 ppm of Eosin Y, 4000 ppm N-vinylcaprolactam,0.54 weight percent triethanolamine, 0.8 weight percent of potassiumphosphate.

In another aspect, the invention features a method of making a surgicalprosthesis. The method includes providing a fabric including a firstlayer formed substantially of non-biodegradable yarn and a second layerformed of biodegradable yarn, providing a liquid formulation including afirst polymer system, a second polymer system, and a photo initiator,placing the fabric over the liquid formulation such that the secondlayer is in fluid contact with the liquid formulation, and exposing theliquid formulation to a light source to activate the photoinitiator soas to cause polymerization of at least one of the polymer systems in theliquid formulation.

Embodiments may include one or more of the following. The polymerizationof at least one of the polymer systems results in the formation of abarrier layer partially embedded within the second layer of the fabric.The first polymer system includes carbodiimide-modified hyaluronic acidand carbodiimide-modified carboxymethylcellulose and the second polymersystem includes poly(ethylene glycol)-trimethylene carbonate/lactatemulti-block polymers endcapped with acrylate esters. The photoinitiatorincludes Eosin Y. The liquid formulation further includes an accelerantand at least one buffer. In some embodiments, the liquid formulationincludes accelerant, such as, for example, n-vinylcaprolactam, and twobuffers, such as triethanolamine and potassium phosphate.

Embodiments may also include one or more of the following. The lightsource used to activate the photoinitiator is an LED array having anintensity of about 1 to about 100 mW/cm². The surgical prosthesis formedis dried in a convection oven.

In general, in a further aspect, the invention features a method ofrepairing an opening in a wall enclosing a body cavity of a patient. Themethod includes providing a surgical prosthesis, such as, for example,the surgical prostheses described above, and securing the surgicalprosthesis over the wall opening of the patient such that the adhesionbarrier faces viscera or tissue from which adhesion is to be prevented.

Embodiments may have one or more of the following advantages. Thesurgical prosthesis can be used to treat an opening in a patient's bodycavity with minimal or no adhesion formation. Due to the incorporationof the adhesion barrier within the mesh, there is a strong mechanicalconnection between the hydrophilic adhesion barrier and a hydrophobicpolypropylene mesh. As a result, the likelihood of delamination of theadhesion barrier from the mesh is decreased. Another advantage of thesurgical prosthesis is the inclusion of interlooping or intertwiningyarns forming the two layers of the mesh. The use of the interlooping orintertwining yarns reduces or even eliminates reliance on adhesives toform the surgical prosthesis.

As used herein “non-biodegradable” means a material that containscomponents that are not readily degraded, absorbed, or otherwisedecomposed when present in a body cavity.

As used herein “biodegradable” means a material that contains componentsthat can be degraded and/or absorbed at some time after implantation ofthe surgical prosthesis, such as within weeks or months followingimplantation.

As used herein “substantially” means predominantly but not wholly thatwhich is specified. When a layer is said to be substantiallynon-biodegradable, it refers to a layer that is predominantly composedof non-biodegradable material, but for a small volume of the layer wherethe non-biodegradable material intertwines with the biodegradablematerial. When a layer is said to be substantially biodegradable, itrefers to a layer that is predominantly composed of biodegradablematerial, but for a small volume of the layer where the biodegradablematerial intertwines with the non-biodegradable material.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features andadvantages of the invention will be apparent from the description anddrawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1A is a cross-sectional view of an embodiment of a surgicalprosthesis.

FIG. 1B is a surface view of a first surface of the surgical prosthesisof FIG. 1A.

FIG. 1C is a surface view of a second surface of the surgical prosthesisof FIG. 1A.

FIG. 2A is a cross-sectional view of a mesh used to form a surgicalprosthesis.

FIG. 2B is a surface view of a non-biodegradable layer of the mesh ofFIG. 2A

FIG. 2C is a surface view of a biodegradable layer of the mesh of FIG.2A.

FIG. 3A is a surface view of another embodiment of a mesh used to form asurgical prosthesis.

FIG. 3B is a cross-sectional view of the mesh of FIG. 3A.

FIG. 4 is a surface view of an opening in a wall of a body cavity beforerepair.

FIG. 5 is a surface view of the opening of FIG. 4 with the surgicalprosthesis shown in FIG. 1A properly positioned for repair.

FIG. 6 is a surface view of the opening and surgical prosthesis in FIG.5, the opening now being closed by sutures.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

Referring to FIGS. 1A-C, a surgical prosthesis 10 for repairing anunwanted opening in a body cavity, such as an opening in the abdomen,includes an adhesion barrier 20 supported by a three-dimensional mesh30. The three-dimensional mesh 30, shown with the adhesion barrier 20 inFIGS. 1A-C and without the adhesion barrier 20 in FIGS. 2A-C, is formedof biodegradable yarn 32 and non-biodegradable yarn 34 that define atleast two layers (here, two). Referring particularly to FIG. 1B, one ofthe at least two layers, layer 33, forms a first mesh surface 35 and issubstantially non-biodegradable. Referring particularly to FIG. 1C,another of the at least two layers, layer 37, forms a second meshsurface 39 and is substantially biodegradable. Layers 33 and 37 areconnected together by a biodegradable binding yarn 40. An adhesionbarrier 20, which substantially prevents adhesions from forming on thesurgical prosthesis, is formed directly on (e.g., polymerized on)biodegradable layer 37, thereby interconnecting adhesion barrier 20 tomesh 30.

Prior to applying adhesion barrier 20 to mesh 30 to form surgicalprosthesis 10, mesh 30 has an uncompressed thickness of between about2.5 and 3.0 millimeters, an areal density of about 13 to 16 g/ft², andincludes a macroporous structure (e.g., having a pore size of about 100microns or more) that is accessible from first mesh surface 35 andsecond mesh surface 39. After applying adhesion barrier 20 to mesh 30and air drying, surgical prosthesis 10 has a thickness between about0.45 and 0.9 millimeters, an areal density of about 18 to 21 g/ft², andincludes a macroporous structure that is accessible only from the firstmesh surface 35. That is, adhesion barrier 20 is applied to mesh 30 sothat adhesion barrier 20 extends past second mesh surface 39 and intothe macroporous structure of biodegradable layer 37 of mesh 30, therebyat least partially filling the macroporous structure of layer 37. Insome embodiments, the macroporous structure of layer 37 is replaced witha microporous structure (e.g., having a pore size of about 50 microns orless, preferably having a pore size of 10 microns or less).

The Mesh

Mesh 30 is any woven or knitted structure that includes biodegradableyarns 32 and non-biodegradable yarns 34. Typically, the ratio ofnon-biodegradable yarns to biodegradable yarns in the mesh ranges fromabout 0.1 to 9. In certain embodiments, the ratio of non-biodegradableyarns to biodegradable yarns is 1 to 2.33. Mesh 30 has a structure thaton one side allows adhesion barrier 20 to become entangled andinterlocked within biodegradable layer 37, and on the opposite side hasa structure that provides a strong support frame for cellular ingrowthand repair. In some embodiments, such as, for example, the embodimentillustrated in FIGS. 2A-C, mesh 30 includes biodegradable andnon-biodegradable yarns that have been intertwined and/or interlooped todefine layers 33 and 37. In certain embodiment, such as, for example,the embodiment shown in FIGS. 3A-B, mesh 30′ includes a preformednon-biodegradable mesh 33′ formed of non-biodegradable yarns 34 and apreformed biodegradable mesh 37′ formed of biodegradable yarns 32 thatare stitched together with biodegradable binding yarn 40.

In general, the non-biodegradable yarn 34 in mesh 30 can be selected asdesired. Typically, non-biodegradable yarn 34 is selected to bebiocompatible with the subject in whom surgical prosthesis 10 is to beused. In addition, non-biodegradable yarn 34 used in mesh 30 typicallyhas a straight tensile strength between about 1.0 and 2.0 lbs asmeasured based on a method according to ASTM standard #D2256-95A. Insome embodiments, the non-biodegradable yarn 34 is a monofilament yarnhaving a diameter of about 0.001 inches to about 0.010 inches. Incertain embodiments, the non-biodegradable yarn 34 has a diameter ofabout 0.005 inches. Examples of non-biodegradable yarns includepolypropylene and polyethylene terephthalate.

Biodegradable yarns 32, 40 in mesh 30 can also be selected as desired.In general, the biodegradable yarn is selected to be compatible withadhesion barrier 20. In some embodiments, the biodegradable yarn ishydrophilic. In certain embodiments, biodegradable yarns 32 used in mesh30 has a straight tensile strength between about 0.4 and 1.8 lbs asmeasured by a method based on ASTM standard #D2256-95A. In someembodiments, the biodegradable yarn is a 90 denier or less multifilamentyarn. The multifilament yarn can include 10 to 50 monofilament fibersthat each has a thickness of about 0.0006 inches. Examples ofbiodegradable yarns include poly(glycolic) acid (PGA), polylactic acid(PLA), polydioxanone (PDO), polycaprolactone (PCL), calcium alginate,and copolymers thereof.

In some embodiments, the non-biodegradable and/or biodegradable yarnscan be coated with a lubricant in order to facilitate knitting of theyarns. Suitable examples of lubricants for the non-biodegradable andbiodegradable yarns include nontoxic hydrophobic waxes such as, forexample, esters of fatty acid alcohols, or hydrophilic lubricants suchas, for example, polyalkyl glycols. One specific spin finish that yieldsparticularly good results for the non-biodegradable yarn is LurolPP-3772 (Goulston Technologies, Inc., Monroe, N.C.). A spin finish blendof Poloxamer 184, Polysorbate 20, sodium lauryl sulfate, propyleneglycol methyl ether, and toluene has yielded good results for thebiodegradable yarn.

The Adhesion Barrier

The adhesion barrier 20 composition may comprise a gel, foam, film ormembrane made of a bioresorbable material. The adhesion barrier 20 maybe prepared from one or more components selected from hyaluronic acidsand any of its salts, carboxymethyl cellulose and any of its salts,oxidized regenerated cellulose, collagen, gelatin, phospholipids, andthe first and second polymer systems described below, as well as anycrosslinked or derivatized forms thereof. In some embodiments, thebarrier is made from a material capable of forming a hydrogel whencontacted with an aqueous fluid, such as saline, phosphate buffer, or abodily fluid.

In a preferred embodiment, the adhesion barrier 20 composition comprisesa mixture of at least two polymer systems. The first polymer systemincludes a crosslinked biodegradable multi-block polymer hydrogel havinga three-dimensional polymer network. The second polymer system comprisesat least one polyanionic polysaccharide modified by reaction with acarbodiimide compound.

The crosslinked polymer hydrogel of the first polymer system compriseshydrophilic blocks, biodegradable blocks, and crosslinking blocks formedduring the polymerization of macromers. The macromers are largemolecules that comprise at least one hydrophilic block, at least onebiodegradable block and at least one polymerizable group. One or more ofthese blocks may be polymeric in nature. At least one of thebiodegradable blocks comprises a linkage based on a carbonate or estergroup, and the macromers can contain other degradable linkages or groupsin addition to carbonate or ester groups. Suitable macromers to formpolymer hydrogels and methods of preparing them have been described inU.S. Pat. No. 6,083,524 and U.S. Pat. No. 5,410,016, the disclosures ofwhich are incorporated herein by reference.

Suitable hydrophilic polymeric blocks include those which, prior toincorporation into the macromer, are water-soluble such as poly(ethyleneglycol), poly(ethylene oxide), partially or fully hydrolyzed poly(vinylalcohol), poly(vinylpyrrolidone), poly(ethyloxazoline), poly(ethyleneoxide)-co-poly(propylene oxide) block copolymers (poloxamers andmeroxapols), poloxamines, carboxymethyl cellulose, hydroxyalkylatedcelluloses such as hydroxyethyl cellulose and methylhydroxypropylcellulose, polypeptides, polynucleotides, polysaccharides orcarbohydrates such as Ficoll® polysucrose, hyaluronic acid, dextran,heparin sulfate, chondroitin sulfate, heparin, or alginate, and proteinssuch as gelatin, collagen, albumin, or ovalbumin. The preferredhydrophilic polymeric blocks are derived from poly(ethylene glycol) andpoly(ethylene oxide).

The biodegradable blocks are preferably hydrolyzable under in vivoconditions. Biodegradable blocks can include polymers and oligomers ofhydroxy acids, carbonates or other biologically degradable polymers thatyield materials that are non-toxic or present as normal metabolites inthe body. Preferred oligomers or polymers of hydroxy acids arepoly(glycolic acid), also called polyglycolate, poly(DL-lactic acid) andpoly(L-lactic acid), also called polylactate. Other useful materialsinclude poly(amino acids), poly(anhydrides), poly(orthoesters), andpoly(phosphoesters). Polylactones such as poly(epsilon-caprolactone),poly(delta-valerolactone), poly(gamma-butyrolactone) andpoly(beta-hydroxybutyrate), for example, are also useful. Preferredcarbonates are derived from the cyclic carbonates, which can react withhydroxy-terminated polymers without release of water. Suitablecarbonates are derived from ethylene carbonate (1,3-dioxolan-2-one),propylene carbonate (4-methyl-1,3-dioxolan-2-one), trimethylenecarbonate (1,3-dioxan-2-one) and tetramethylene carbonate(1,3-dioxepan-2-one).

Polymerizable groups are reactive functional groups that have thecapacity to form additional covalent bonds resulting in macromerinterlinking. Polymerizable groups specifically include groups capableof polymerizing via free radical polymerization and groups capable ofpolymerizing via cationic or heterolytic polymerization. Suitable groupsinclude, but are not limited to, ethylenically or acetylenicallyunsaturated groups, isocyanates, epoxides (oxiranes), sulfhydryls,succinimides, maleimides, amines, imines, amides, carboxylic acids,sulfonic acids and phosphate groups. Ethylenically unsaturated groupsinclude vinyl groups such as vinyl ethers, N-vinyl amides, allyl groups,unsaturated monocarboxylic acids or their esters or amides, unsaturateddicarboxylic acids or their esters or amides, and unsaturatedtricarboxylic acids or their esters or amides. Unsaturatedmonocarboxylic acids include acrylic acid, methacrylic acid and crotonicacid or their esters or amides. Unsaturated dicarboxylic acids includemaleic, fumaric, itaconic, mesaconic or citraconic acid or their estersor amides. Unsaturated tricarboxylic acids include aconitic acid ortheir esters or amides. Polymerizable groups may also be derivatives ofsuch materials, such as acrylamide, N-isopropylacrylamide,hydroxyethylacrylate, hydroxyethylmethacrylate, and analogous vinyl andallyl compounds.

The polymerizable groups are preferably located at one or more ends ofthe macromer. Alternatively, the polymerizable groups can be locatedwithin the macromer. At least a portion of the macromers may containmore than one reactive group per molecule so that the resultinghydrophilic polymer can be crosslinked to form a gel. Macromers havingtwo or more polymerizable groups per molecules are called hereincrosslinkers. The minimal proportion of crosslinkers required will varydepending on the desired properties of the hydrogel to be formed and theinitial macromer concentration in solution. The proportion ofcrosslinkers in the macromer solution can be as high as about 100% ofall macromers in the solution. For example, the macromers include atleast 1.02 polymerizable groups on average, and, more preferably, themacromers each include two or more polymerizable groups on average.Poloxamines, an example of water-soluble polymer component suitable toform a hydrophilic block, have four arms and thus may readily bemodified to include four polymerizable groups.

Examples of preferred macromers are illustrated below:

where the polyethylene glycol repeat unit is —(CH₂—CH₂—O)_(x)— or(PEG)_(x), trimethylene carbonate repeat unit is —(C(O)—O—(CH₂)₃—O)_(w)—or (TMC)_(w); lactic acid residue is —(O—CH(CH₃)—CO)_(y)— or (L)_(y);acrylate residue is CH₂═CH—CO— or A, and q, w, w′, y, y′ and x areintegers.A-(L)_(y)-(TMC)_(w)-[(PEG)_(x)-(TMC)_(w′)]_(q)-(L)_(y′)-AA-(L)_(y)-[(PEG)_(x)-(TMC)_(w′)]_(q)-(L)_(y′)-AA-[(PEG)_(x)-(TMC)_(w′)]_(q)-(L)_(y)′-A]

Polymerization of the macromers can be initiated by photochemical means,by non-photochemical like redox (Fenton chemistry) or by thermalinitiation (peroxide etc). Suitable photochemical means include exposureof the macromer solution to visible light or UV light in the presence ofa photoinitiator such as UV or light sensitive compounds such as dyes,preferably eosin Y.

Polymerization of the macromers may be conducted in the presence ofsmall amounts of monomers which act as accelerant of the polymerizationreaction. Preferably the monomers represent 2% or less of the totalcontent of the polymerizable material, more preferably 1% or less, andyet usually about 4,000 ppm. A preferred accelerant is vinylcaprolactam.

In the discussion below and the examples, macromers may be designated bya code of the form xxkZnA_(m), where xxk represents the molecular weightin Daltons of the backbone polymer, which is polyethylene glycol (“PEG”)unless otherwise stated, with x as a numeral and k as the multiplier forthousands; Z designates the molecular unit from which the biodegradableblock is derived from and may take the value one or more of L, G, D, C,or T, where L is for lactic acid, G is for glycolic acid, D is fordioxanone, C is for caprolactone, T is for trimethylene carbonate; n isthe average number of degradable groups randomly distributed on each endof the backbone polymer; A is for acrylate and m for the number ofpolymerizable groups per macromer molecules. Thus 20 kTLA₂ as used inthe Example section is a macromer with a 20×10³ Da polyethylene glycolcore with an average of first trimethylene carbonate residues (7 or moreresidues per macromers, in average about 12) and lactic acid residues (5or less residues per macromers) sequentially extending on both ends ofthe glycol core and randomly distributed between both ends thenterminated with 2 acrylate groups.

The second polymer system comprises at least one polyanionicpolysaccharide modified by a carbodiimide. Methods of preparation ofthese modified polymers have been described in U.S. Pat. No. 5,017,229and U.S. Pat. No. 5,527,983, the entire disclosures of which areincorporated herein by reference.

Suitable polyanionic polysaccharides may be selected from one or more ofthe following, hyaluronic acid, carboxymethyl cellulose, carboxymethylamylose, carboxymethyl chitosan, chondroitin sulfate, dermatan sulfate,heparin, heparin sulfate, alginic acid, and any of their salts,including sodium, potassium, magnesium, calcium, ammonium or mixturesthereof.

The polyanionic polysaccharides are modified by reaction with acarbodiimide to form N-acyl urea derivatives and render them waterinsoluble, however, they remain very hydrophilic and thus absorb waterto form gels also referred to as hydrogels. The reaction conditions withcarbodiimides are well described in the cited patents above. Preferredcarbodiimides are those that exhibit water solubility, such as1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide (EDC) or1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide methiodide (ETC).

After reaction with carbodiimide, the modified polyanionicpolysaccharide compositions may be dried to less than about 20% moisturecontent, preferably about 9% and stored in powder form.

To prepare the barrier compositions, the modified polyanionicpolysaccharide composition may be rehydrated in buffer alone to form afluid gel before mixing with the macromer solution of the second polymersystem. The barrier composition may also be prepared by rehydrating themodified polyanionic polysaccharide composition in the buffer solutionof the macromer solution of the second polymer system, thereby forming afluid gel that comprises both polymer systems. The fluid gel is thencast in a dish having the desired shape and exposed to polymerizingcondition, such a UV or visible light to form a barrier composition ofthe invention. Once the macromers in the fluid gel have polymerized, thebarrier composition forms a hydrated soft rubbery material that hasimproved handling properties and is resistant to tear. The barriercomposition may be polymerized into desired shape articles like sheets,discs, tubes or rods by selecting appropriate casts or by extrusion.

The barrier composition may be further dried for packaging and thenre-hydrated prior to implantation into the body of a patient (such as ahuman or animal such as non-human mammals). The barrier composition orshaped article is preferably dried to a moisture content of less thanabout 5%, and preferably less than about 2% in a convection oven to forma film or membrane, or freeze-dried under a vacuum to form a foam. Thebarrier composition may be used alone to treat or prevent complicationsfrom surgeries (e.g., to prevent the formation of adhesions).

The barrier composition may be deposited on the surface of medicaldevices such as fabrics (e.g., woven or non-woven fabrics, such asmeshes, knits, fleeces and mattes) as a fluid and then dried by anyknown method. In embodiments in which the barrier composition is in theform of a film or a foam, the barrier composition can be laminatedand/or stitched to the fabric by any known method. In embodiments inwhich the barrier composition is formed from a solution includingmacromers (e.g., a fluid gel), the barrier composition can be depositedon the fabric by placing the fabric in the fluid gel and initiatingpolymerization. Hydrophobic fabrics will float on the surface of thefluid gel. Less hydrophobic fabrics, such as fabrics having polar groups(e.g., esters, amides, ketones, and carbonates), may penetrate throughthe surface into the fluid gel to a certain extent such thatpolymerization of functional groups on the macromers in the presence ofthe fabric provides for greater adherence of the barrier composition tothe fabric. In composite multilayered fabrics of the invention where onelayer is less hydrophobic than the other, when placing the lesshydrophobic side of the fabric over the fluid gel, the fibers on thatside of the fabric penetrate the fluid gel, while the hydrophobic fiberson the other side of the fabric float over the fluid gel. Once thecomposition is polymerized, a portion of the polymer network entraps theless hydrophobic fibers of the fabric providing added adhesion strengthof the barrier on the fabric.

Once applied to the device or fabric, the barrier composition may bedried for long-term storage and packaging, then rehydrated prior toimplantation into the body of a patient.

In general, the adhesion barrier can be in the form of a film, foam, orgel. In some embodiments, the adhesion barrier has a density of lessthan about 20 grams of total polymer per square foot. In someembodiments, the adhesion barrier has a density of about 4 to about 6grams of total polymer per square foot. In certain embodiments, theadhesion barrier has a density of about 5 grams of total polymer persquare foot.

Referring to FIGS. 4-6, surgical prosthesis 10 can be used to repair anopening 100 in a wall 110 of a patient's body cavity 120 that exposes avisceral surface 122 (e.g., bowels, omentum). To repair opening 100, amedical professional inserts surgical prosthesis 10 through opening 100and into body cavity 120. Surgical prosthesis 10 is positioned such thatlayer 37 faces the visceral surface 122 and layer 33 faces wall 110 andcovers opening 100. Once the surgical prosthesis 10 is positioned, themedical professional closes opening 100 with sutures 130.

In time, adhesion barrier 20 (e.g., about 3 to 28 days) and layer 37(e.g., about 60 to 90 days) of mesh 30 are absorbed by the body, leavinglayer 33 in contact with visceral surface 122. However, by the time theadhesion barrier 20 has been absorbed, opening 100 has healed to anextent (e.g., a new peritoneal surface has formed over opening 100) thatthe likelihood of adhesions forming between viscera and surgicalprosthesis 10 is minimal. In addition, layer 37, which is formed frombiodegradable yarn 32, provides a second defense against adhesionprevention. As described above, layer 37 is absorbed by the body over aperiod of about 60 to 90 days. As a result, any adhesions that may haveformed due to a failure of adhesion barrier 20 or after adhesion barrier20 was absorbed will be released as layer 37 is absorbed.

While both adhesion barrier 20 and layer 37 are absorbed by a patient'sbody, layer 33 of the surgical prosthesis 10 becomes incorporated intowall 110. Layer 33, made substantially from non-biodegradable yarn 34,provides a strong, macroporous structure that allows for tissue ingrowth(e.g., layer 33 has a pore size of 100 microns or greater) to repairopening 100.

In general, surgical prosthesis 10 can be prepared using any desiredmethod. In certain embodiments, surgical prosthesis 10 is prepared asfollows. First, the three-dimensional mesh 30 is created usingbiodegradable yarn 32 and non-biodegradable yarn 34. The yarns 32, 34are threaded into an industrial knitting machine, such as adouble-needle bar knitting machine. Yarns 32 and 34 are knitted togetherusing any knitting pattern that creates a three-dimensional macroporousstructure having biodegradable layer (e.g., layer 37) andnon-biodegradable layer (e.g., layer 33). In certain embodiments, mesh30 is formed by knitting together a non-biodegradable yarn, a firstbiodegradable yarn, and a second biodegradable yarn, wherein thenon-biodegradable yarn and the first biodegradable yarn form layers 33and 37 respectively and the second biodegradable yarn binds layers 33and 37 together. To apply adhesion barrier 20 to mesh 30, a liquidformulation including a photoinitiator and adhesion barrier precursorcomponents is added to a glass tray. Then mesh 30 is placed within thetray with the bioabsorbable side (layer 37) facing the bottom of thetray (e.g., the bioabsorbable layer in fluid contact with the liquidformulation). The liquid formulation is photopolymerized by exposing thetray to a light source that activates the photoinitiator (e.g., a lightsource having a wavelength of about 450 nm to about 550 nm and anintensity of about 1 mW/cm² to about 100 mW/cm²). As a result ofphotoinitiation, a hydrogel is formed within the tray around at least aportion of layer 37. The hydrogel is then dried so that the resultingmesh/hydrogel has a moisture content of less than about 2% (e.g., lessthan about 1.2%, such as about 0.8%). The mesh/dried hydrogel is thensterilized to form surgical prosthesis 10.

It is believed that the hydrogel does not form within the porousstructure of layer 33 during photopolymerization for at least threereasons. First, the amount of liquid formulation added to the glass trayis controlled to produce a hydrogel having a thickness that is equal toor less than the thickness of layer 37. For example, approximately onemilliliter of solution including photoinitiator and adhesion barrierprecursor components is added per square inch of tray. Then, a meshhaving an areal density of 14.5 g/ft² with a biodegradable layer havingan uncompressed thickness of about 2.5 millimeters is added to the tray.Second, because there is an incompatibility between non-biodegradableyarn 34 (e.g., hydrophobic) and the hydrophilic precursor components,the liquid formulation tends not to wick up into the pore structure oflayer 33. As result, when the liquid formulation is polymerized it formsthe hydrogel only around layer 37. Third, when the polymerized hydrogel,which is mostly water, is air-dried it decreases greatly in thickness.As a result, the adhesion barrier is only around layer 37.

The following examples are illustrative and not intended to be limiting.

Example 1

To manufacture the three-dimensional mesh, two 5 mil polypropylenemonofilament fibers (Shakespeare Monofilament and Specialty Polymers,Columbia, S.C.), a 45 denier polyglycolic acid multifilament fiber(Teleflex Medical, Coventry, Conn.), and a 90 denier polyglycolic acidmultifilament fiber (Teleflex Medical, Coventry, Conn.) were threadedinto a double needle bar knitting machine (Karl MayerTextimaschinenfabrik GmbH, Oberlshausen, Germany). Referring to FIGS.2A-C, the fibers were co-knitted by Secant Medical, Perkasie, Pa. usingthe bar pattern given below to create a mesh that had a layer formedsubstantially of poly(glycolic) acid on the front (FIG. 2C), a layerformed substantially of polypropylene on the back (FIG. 2B), and apolyglycolic acid binder fiber connecting the two layers together (FIG.2A).

TABLE 1 Mesh Bar Pattern Bar Fiber Pattern 1  5 mil polypropylenemonofilament fiber fully 1/0, 1/2, 2/3, 2/1 threaded 2  5 milpolypropylene monofilament fiber fully 2/3, 2/1, 1/0, 1/2 threaded 3 45denier polyglycolic multifilament fiber half 1/0, 1/2 set threaded 4 90denier polyglycolic multifilament fiber half 1/0, 2/3 set threaded

After fabrication, the three-dimensional mesh was cleaned in a scouringsystem and annealed at 150° C. in a heat setting frame to stabilize thethree-dimensional mesh structure. The resulting three-dimensional meshhad on average 18 wales per inch, 28 courses per inch, a thickness of0.0319 inches, an areal density of 4.60 ounce per square yard, a burststrength of 762±77 Newtons as measured by a method based on ASTMstandard #D3787-89, a tear propagation strength in a direction parallelto the machine direction of 127±21 Newtons and perpendicular to themachine direction of 203±15 Newtons as measured by a method based onASTM standard #D5587-96, a suture retention strength in the directionparallel to the machine direction of 60±12 Newtons and perpendicular tothe machine direction of 80±9 as measured by the pullout force of a 20gauge needle placed five millimeters from the mesh edge.

Example 2

A liquid formulation including the precursors for adhesion barrier 20was made as follows. First 1 gram of modified and irradiated hyaluronicacid/carboxymethylcellulose (HA/CMC) powder prepared as described inU.S. Pat. Nos. 5,017,229 and 5,527,893, was mixed with 86 grams ofdeionized water under high shear to form a suspension. Next, 2.5 gramsof a photopolymerizable compound powder based on poly(ethyleneglycol)-trimethlyene carbonate/lactate multi-block polymers endcappedwith acrylate esters (20 kTLA₂) and described in U.S. Pat. No.6,177,095, was blended into the suspension. Then, 40 ppm, of Eosin Y, aphotoinitiator, 4000 ppm of N-vinylcaprolactam, an accelerant, 0.54grams of triethanolamine, a buffer and electron transfer component, and0.8 grams of potassium phosphate, a second buffer, were blended into thesuspension. To complete the liquid formulation, additional deionizedwater was added to bring the final volume to 100 grams.

Example 3

The mesh as described in Example 1 was combined with the adhesionbarrier as described in Example 2 to form a surgical prosthesis for softtissue repair with one surface for tissue ingrowth and one surface withanti-adhesion properties.

To join the adhesion barrier to the mesh, the liquid formulationdescribed in Example 2 was cast onto a glass plate at a casting densityof 5 grams of total polymer per square foot. The mesh was placed intothe liquid formulation with the polyglycolic acid layer facing the glassplate. The area was illuminated with a visible light from an LED array(450-550 nm) at an intensity of about 4 mW/cm² for 120 seconds. Thephotopolymerized composite was dried in a convection oven at 50° C. for4 hours. The dried composite was peeled from the glass plate, cut tovarious sizes, packaged, and ethylene oxide sterilized.

Example 4

The surgical prosthesis as prepared in Example 3 was evaluated in arabbit hernia repair model with abraded bowel.

Twenty sexually mature female New Zealand White Rabbits each weighingbetween 3 kg and 5 kg at the time of surgery, were anesthetized andsubjected to a 5 cm by 7 cm full thickness abdominal muscle excision andcecal abrasion surgical procedure. Each rabbit received either a 5 cm by7 cm piece of a polypropylene mesh or the surgical prosthesis asprepared in Example 3. All rabbits were allowed to recover from thesurgical procedure.

Twenty-eight days after the surgery, the rabbits were euthanized andoverall performance of the materials, including adhesion formation andtissue ingrowth was evaluated. Adhesion formation was evaluated andvisually scored for extent coverage by adhesion. The following scale wasused during the visual examination: 0=no adhesions, 1=25% or less of thedefect covered by adhesions, 2=26% to 50% of the defect covered byadhesion, 3=51% to 75% of the defect covered by adhesions, 4=more than75% of the defect covered by adhesions.

In addition to visual examinations, image analysis was used to calculatethe total surface area of the defects and the surface area covered byadhesions. Mechanical testing and SEM samples were also collected andanalyzed. The results are described in Tables 2 and 3 below.

TABLE 2 Rabbit Hernia Repair with Abraded Bowel Adhesion ReductionEfficacy Results % Defect % Animals % with No Group Mean Extent withwith No Dense Bowel N = 10 of Adhesions Adhesions Adhesions AdhesionsPolypropylene 2.9 ± 0.3 47.3 ± 6.3  0 0 Mesh Surgical  1.3 ± 0.2* 14.3 ±5.0* 0  60** Prosthesis as Prepared in Example 3 *p < 0.05 Tukey KramerHSD analysis **p < 0.05 Chi-Square analysis

TABLE 3 Rabbit Hernia Repair with Abraded Bowl Tissue IncorporationResults Group Max Load (N) ± SEM Polypropylene Mesh 33.7 ± 1.2 SurgicalProsthesis as 29.7 ± 1.3 Prepared in Example 3 {circumflex over ( )}p <0.05 Tukey-Kramer HSD analysis

The results in Table 2 indicate that the surgical prosthesis asdescribed in Example 3 performed significantly well in preventing densebowel adhesions in vivo. In addition, the surgical prosthesis describedin Example 3 had excellent tissue incorporation strength as shown inTable 3.

Example 5

A surgical prosthesis was prepared by placing the bioabsorbablepolyglycolic acid side of the mesh as described in Example 1 into 10 to12 ml of a liquid formulation in a polystyrene dish having an area of56.7 square centimeters. For the liquid formulation, 2 grams ofcarbodiimide-modified HA/CMC powder in 90 grams of water was blendedwith 5% 20 kTLA₂ macromer in 100 grams of deionized water. Additionalsolution consisting of 40 ppm Eosin Y, 4000 ppm N-vinylcaprolactam, 1.08grams of triethanolamine, and 1.6 grams of potassium phosphate indeionized water were added to bring the final volume to 200 grams.

The liquid formulation was then photopolymerized into a hydrogel usingan LED array (450-550 nm) at an intensity of about 4 mW/cm² for 45seconds. The mesh with hydrogel was freeze-dried at approximately −30°C. and 200 mTorr, before being peeled from the polystyrene dish. Theresulting surgical prosthesis was compressed at 5,000 lbs force for 10seconds between Teflon coated plates and double packaged in vaporpermeable pouches. The surgical prosthesis were sterilized by exposureto ethylene oxide before use.

Using the processes described in Example 4, a 5 cm by 7 cm piece ofeither a polypropylene mesh or the surgical prosthesis described in thisexample was implanted in a rabbit hernia repair model with abraded bowelin 10 rabbits for 14 days and in 10 different rabbits for 28 dates. Theresults are shown in Table 4 below.

TABLE 4 Rabbit Hernia Repair with Abraded Bowel Adhesion ReductionEfficacy Results Mean % Defect % Animals % with No Extent of with withDense Bowel Adhesions Adhesions No Adhesions Adhesions Group: 14 DaysPolyproylene 3.0 ± 0.6  65 ± 11 0 0 Mesh Surgical 1.0 ± 0.3* 16 ± 8* 2040 Prosthesis as Prepared in Example 5 Group: 28 Days Polypropylene 2.4± 0.3  42 ± 13 0 0 Mesh Surgical 1.0 ± 0.1* 12 ± 3* 10 20 Prosthesis asPrepared in Example 5 *p < 0.05 Tukey Kramer HSD analysis

The adhesion reduction efficacy results showed that the surgicalprosthesis described in this example performed well in preventingadhesions in vivo.

Example 6

A liquid formulation of 2.5% 20 kTLA2, 40 ppm of Eosin Y, 4000 ppm ofN-vinylcaprolactam, 0.54% of triethanolamine, 0.8% of potassiumphosphate, and 1% carbodiimide-modified HA/CMC was prepared and 32 ml ofthe liquid formulation was cast on a 32 square inch glass plate. Themesh from Example 1 was placed into the liquid formulation with thebiodegradable polyglycolic acid side down. The liquid formulation wasphotopolymerized by exposing the liquid formulation to a visible lightemitting diode array having an intensity of about 4 mW/cm² for fourminutes. The resulting mesh reinforced with hydrogel was allowed to airdry at 50° C. for four hours, before the glass plate was removed. Thereinforced mesh was then dehydrated at 100° C. for seven hours to formthe surgical prosthesis.

Example 7

The surgical prosthesis of Example 6 was tested for surgical handlingproperties. The abdomino-pelvic cavity of an adult domestic pig was usedto simulate a laparoscopic clinical application of the surgicalprosthesis.

The surgeon who inserted the surgical prosthesis into theabdomino-pelvic cavity of the adult domestic pig was able todifferentiate the correct sidedness of a wet and a dry surgicalprosthesis. Before insertion, the surgeon attached stay sutures at eachend of the surgical prosthesis. The surgeon then hydrated the surgicalprosthesis in saline for a few seconds before delivering the prosthesisthrough a 12 millimeter trocar. A portion of the stay sutures werepassed through the abdominal wall and secured. The surgical prosthesiswas tacked to the sidewall using helical titanium tacks. Moderatemanipulation of the surgical prosthesis during placement did not causeany delamination. Overall, the surgeon was pleased with the handling,placement, and durability of the surgical prosthesis.

Example 8

A mesh for a surgical prosthesis was formed by stitching together apolyglycolic acid (PGA) nonwoven felt fabric with a mass/area of about 7mg/cm² and a thickness of about 1 millimeter to a single atlaspolypropylene mesh with a mass area of 9.4 mg/cm² and made from 6 milpolypropylene fiber. The PGA nonwoven felt fabric was obtained fromScaffix International (Dover, Mass.) and the single atlas polypropylenemesh was obtained from Genzyme Biosurgery (Fall River, Mass.).

The nonwoven felt fabric was stitched to the polypropylene mesh usingBondek® polyglycolic acid suture size 6-0 (provided by GenzymeBiosurgery, Coventry, Conn. now Teleflex Medical, Coventry, Conn.) in astandard sewing machine. The mass/area of the mesh as stitched togetherwas 16 to 17 mg/cm².

To form a surgical prosthesis, the mesh was placed with the PGA nonwovenfelt side down into 10 ml of a 2.5% liquid formulation of 20 kTLA₂, 40ppm of Eosin Y, 4000 ppm of N-vinylcaprolactam, 0.54% oftriethanolamine, and 0.8% of potassium phosphate in a polystyrene dishhaving an area of 56.7 cm². The liquid formulation was photopolymerizedinto a hydrogel with five 40 second cycles from a xenon light source.The mesh with the hydrogel was freeze-dried at −30° C. and 200 mTorr. Awell incorporated, flexible dry sample resulted. The surgical prosthesiswas sterilized by exposure to ethylene oxide. After initial hydration,the surgical prosthesis had good wet handling durability.

Example 9

A mesh for a surgical prosthesis was formed using the process describedin Example 8. The nonwoven felt fabric side was placed down into a 56.7cm² polystyrene dish having 12 grams of a suspension including 2.3%carbodiimide-modified HA/CMC as obtained from Genzyme Corporation(Framingham, Mass.) and 0.073 ml of glycerol, a plasticizer. The dishincluding the suspension and the mesh was left to air-dry overnight.

A high quality composite sample resulted with all components firmlyattached and a mass/area ratio of 21.7 mg/cm². Using scanning electronmicroscopy (SEM), the plasticized HA/CMC membrane was observed to beembedded in the fibers of the nonwoven felt fabric side of the mesh.Some voids, possibly due to air bubbles, were noticeable within theadhesion barrier.

The sample was heated for 7 hours at 100° C. in a convection oven toremove residual moisture. Upon hydration, the hydrophilic, lubricouslayer of HA/CMC was visually noticeable on the one surface of thesurgical prosthesis. The surgical prosthesis had good wet handlingproperties after initial hydration and after 24 hours soaking in waterat room temperature. The hydrated sample could be rubbed vigorouslybetween thumb and forefingers without delamination and could not bepeeled apart by hand.

Example 10

A mesh for a surgical prosthesis was formed using the process describedin Example 8. The nonwoven felt fabric side was placed down into a 56.7cm² polystyrene dish having 5 ml of a 5% solution of 20 kTLA₂, 40 ppm ofEosin Y, 4000 ppm of N-vinylcaprolactam, 0.54% of triethanolamine, 0.8%of potassium phosphate, and 5% hyaluronic acid. The solution was thenphotopolymerized into a hydrogel with four 40 second cycles from a xenonlight source obtained from Genzyme Biosurgery (Lexington, Mass.).

The surgical prosthesis had very good wet handling durability and couldbe used as is or freeze-dried for use at a later time.

Example 11

A mesh for a surgical prosthesis was formed by stitching together aVicryl® knitted mesh formed of polyglactin 910, a copolymer of polyglycolic and polylactic acid fibers and obtained from Ethicon (NewBrunswick, N.J.) to a single atlas polypropylene mesh with a mass areaof 9.4 mg/cm² and made from 6 mil polypropylene fiber and obtained fromGenzyme Biosurgery (Fall River, Mass.).

The Vicryl® knitted mesh was stitched to the polypropylene mesh usingBondek® polyglycolic acid suture size 6-0 (provided by GenzymeBiosurgery, Coventry, Conn. now Teleflex Medical, Coventry, Conn.) in astandard sewing machine. The mass/area of the mesh as stitched togetherwas about 15 mg/cm².

To form the surgical prosthesis, the mesh was placed with the Vicryl®surface down into 5 ml of a 5% solution of 20 kTLA₂, 40 ppm of Eosin Y,4000 ppm of N-vinylacprolactam, 0.54% of triethanolamine, and 0.8% ofpotassium in a polystyrene dish having an area of 56.7 cm³. The solutionwas then photopolymerized into a hydrogel with four 40 second cyclesfrom a xenon light source. The surgical prosthesis was freeze-dried at−30° C. and 200 mTorr. A well-incorporated, flexible, dry surgicalprosthesis resulted. After initial hydration, the surgical prosthesishad good wet handling durability.

All publications, applications, and patents referred to in thisapplication are herein incorporated by reference to the same extent asif each individual publication or patent was specifically andindividually indicated to be incorporated by reference in theirentirety.

All of the features disclosed herein may be combined in any combination.Each feature disclosed may be replaced by an alternative feature servingthe same, equivalent, or similar purpose. Thus, unless expressly statedotherwise, each feature disclosed is only an example of a generic seriesof equivalent or similar features.

Other embodiments are within the scope of the following claims.

What is claimed is:
 1. A method of making a surgical prosthesis, themethod comprising the steps of: providing a fabric comprising a firstlayer formed substantially of non-biodegradable yarn and a second layerformed of biodegradable yarn; providing a liquid formulation comprisingmacromers and an initiator; placing the fabric within the liquidformulation such that the second layer is in fluid contact with theliquid formulation; and exposing the liquid formulation to a lightsource.
 2. The method of claim 1, wherein the initiator is aphotoinitiator.
 3. The method of claim 2, wherein the photoinitiatorcomprises Eosin Y.
 4. The method of claim 1, wherein the liquidformulation further comprises biopolymers, an accelerant and a buffer.5. The method of claim 4, wherein the biopolymers comprise at least onepolyanionic polysaccharide modified by reaction with carbodiimide. 6.The method of claim 4, wherein the buffer comprises triethanolamine. 7.The method of claim 4, wherein the buffer comprises potassium phosphate.8. The method of claim 4, wherein the accelerant comprisesN-vinylcaprolactam.
 9. The method of claim 1, wherein the liquidformulation comprises 1 weight percent of carbodiimide-modifiedhyaluronic acid and carboxymethylcellulose, 2.5 weight percentpoly(ethylene glycol)-trimethlyene carbonate/lactate multi-blockpolymers endcapped with acrylate esters, 40 ppm of Eosin Y, 4000 ppmN-vinylcaprolactam, 0.54 weight percent triethanolamine, 0.8 weightpercent of potassium phosphate.
 10. The method of claim 1, wherein thelight source is an LED array having an intensity of about 1 to about 100mW/cm2.
 11. A method of making a surgical prosthesis, the methodcomprising the steps of: providing a fabric comprising a first layerformed substantially of non-biodegradable yarn and a second layer formedof biodegradable yarn; providing a liquid formulation comprising a firstpolymer system, a second polymer system, and a photoinitiator; placingthe fabric over the liquid formulation such that the second layer is influid contact with the liquid formulation; and exposing the liquidformulation to a light source to activate the photoinitiator so as tocause polymerization of at least one of the polymer systems in theliquid formulation.
 12. The method of claim 11, wherein thepolymerization of at least one of the polymer systems results in theformation of a barrier layer partially embedded within the second layerof the fabric.
 13. The method of claim 12, wherein the first polymersystem comprises carbodiimide-modified hyaluronic acid andcarbodiimide-modified carboxymethylcellulose and the second polymersystem comprises poly(ethylene glycol)-trimethylene carbonate/lactatemulti-block polymers endcapped with acrylate esters.
 14. The method ofclaim 13, wherein the photoinitiator comprises Eosin Y.
 15. The methodof claim 14, wherein the liquid formulation further comprises anaccelerant and at least one buffer.
 16. The method of claim 15, whereinthe liquid formulation further comprises a first buffer and a secondbuffer.
 17. The method of claim 16, wherein the accelerant comprisesN-vinylcaprolactam, the first buffer comprises triethanolamine, and thesecond buffer comprises potassium phosphate.
 18. The method of claim 11,wherein the light source is an LED array having an intensity of about 1to about 100 mW/cm2.
 19. The method of claim 12, further comprisingdrying the fabric and the barrier layer in a connection oven.